Perhaps you should try some spelling variations:
thong trong » thuong trong, thong thong, thong thuong
theo chieu » ho chieu, theo chu, thi chieu
trong mach » trong cac, trong minh, trong anh
mach toan » manh toan, hach toan, mach tuan
trang va » tran van, hang va
toan cau » toan cao, toan ban, toan tap
tang va » tang van, thang va, tang vat

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((theo chieu) OR (theo tieu)) xanh - anh ((tang va) OR (trang va)) thong trong mach toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((theo chieu) or (theo tieu)) xanh - anh ((tang va) OR (trang va)) thong trong mach toan cau~".
• Adding a wildcard symbol may retrieve word variants: ((theo chieu) or (theo tieu)) xanh - anh ((tang va) OR (trang va)) thong trong mach toan cau*.